suraj.sun writes: Modern banknotes contain up to 50 anti-counterfeiting features, but adding electronic circuits programmed to confirm the note's authenticity is perhaps the ultimate deterrent, and would also help to simplify banknote tracking.

A team of German and Japanese researchers created arrays of thin-film transistors (TFTs) by carefully depositing gold, aluminium oxide and organic molecules directly onto the notes through a patterned mask, building up the TFTs layer by layer. The result is an undamaged banknote containing around 100 organic TFTs, each of which is less than 250 nanometres thick and can be operated with voltages of just 3V. Such small voltages could be transmitted wirelessly by an external reader, such as the kind that communicates with the RFID tags found on many products